1. Field of the Invention
The present invention relates to bags of flowable, granular materials, especially pet litter, which can be vertically stacked and shipped on a pallet.
2. Description of the Related Art
Currently, bags of flowable, granular material are typically shipped horizontally and often have substantial headspace/free volume in the bag. Bags stored vertically would provide a larger label viewing area on shelf compared to bags stored horizontally and vertically stacked bags also allow many different product volumes or weights to be shipped in the same footprint. When shipped horizontally, a stable and reversible pallet pattern is a critical determinant in the size of the bag for a given volume of product. Not all bag sizes or volumes are practical with horizontal shipping, thus vertical shipment offers more sizing flexibility. Vertical stacking, for example on a shelf or pallet, also has advantages in terms of handling and display. For horizontally stacked bags, the product in the bag supports the weight of the bags above it, but the bag sidewalls are typically in compression and not in tension. In vertical shipment the bag sidewalls are subjected to horizontal radially directed forces that put the bag sidewalls in tension in the horizontal direction. For this reason, in order to stack flowable, granular materials vertically, these granular materials are typically put into cartons or pails, which have stiff sidewalls. However, bags have advantages in terms of reduced use of material and cost.
Existing vertically stacked bags are generally vacuum packed in order to provide sufficient rigidity or the bags are somehow reinforced on the sidewalls. U.S. Pat. App. 2004/0264814 to Eisenbarth et al. and U.S. Pat. No. 6,220,755 to Brown et al. describe stackable bulk bags with pockets to receive support members. U.S. Pat. No. 6,240,709 to Cook describes a bag for vertical stacking that contains a plurality of vertical sections to provide columnar support for holding the bag upright when the vertical sections are filled with material. U.S. Pat. No. 6,244,443 to Nickell et al. describes an eight-sided bulk bag with stiffened wall panels. U.S. Pat. No. 6,471,402 to Burns discloses horizontal or vertical stacked bags with rigid planar elements that interlock for stacking PCT App. WO98/50279 to Randall et al. describes a stackable hybrid bag/box with a rigid top and diagonal folded flap edges that serve as braces to provide stackability. U.S. Pat. No. 5,950,833 to James discloses a stackable cookie package having substantially cylindrical and tubular cushions for support. U.S. Pat. No. 5,873,655 to Echeverria discloses a stackable, bulk container bag with internal, anchored retaining strips to ensure uniform tensile forces on the walls from top to bottom of the strip. U.S. Pat. No. 5,722,552 to Olson discloses a container bag with a frame for supporting and retaining the bag. U.S. Pat. No. 5,358,335 to LaFleur discloses a stackable bag with an inturned shoulder construction that maintains the generally rectangular cross sectional shape of the bag, even with another bag stacked on top. U.S. Pat. No. 5,193,712 to Kuppersbusch discloses stackable packaging using a carton with a bag inside. While these reinforced bag solutions allow the bags to be stackable, they also increase cost, complexity, and reduce environmental sustainability.
To overcome these problems of the prior art, the current invention is designed to utilize the cost and simplicity advantages of a bag with the stacking stability of pails or carton, without designing structural complexity into the bag walls.
Reference will now be made to the drawings wherein like numerals refer to like parts throughout. As used herein, positional terms, such as “bottom” and “top” and the like, and directional terms, such as “up”, “down” and the like, are employed for ease of description in conjunction with the drawings. Further, the terms “inner”, “interior”, “inwardly” and the like, refer to positions and directions toward the geometric center of embodiments of the present invention and designated parts thereof. The terms “outer”, “exterior”, “outwardly”, and the like, refer to positions and directions away from the geometric center. None of these terms is meant to indicate that the described components must have a specific orientation except when specifically set forth.
Figures illustrating the components of this invention and the container show some conventional mechanical elements that are known and that will be recognized by one skilled in the art. The detailed descriptions of such elements are not necessary to an understanding of the invention, and accordingly, are herein presented only to the degree necessary to facilitate an understanding of the novel features of the present invention.